Diet and physical activity as risk-reducing factors for hidradenitis suppurativa.

BACKGROUND: Hidradenitis suppurativa (HS) is a multifactorial inflammatory skin disease that is considered to be an immune-mediated inflammatory disease (IMID). Up till now, the impact of lifestyle on (the development of) HS has not been thoroughly investigated. OBJECTIVES: To investigate the effect of dietary intake and physical activity (PA) on (the development of) HS. MATERIALS AND METHODS: A nested case-control study was performed within the longitudinal Lifelines Cohort Study, that took place in the Northern Netherlands, and identified 1004 adult eligible HS patients and 5000 age-matched controls. Dietary data were collected using a validated food frequency questionnaire, subsequently translated to the Lifelines Diet Score (LLDS), alternate Mediterranean Diet Score (aMED) and Dutch Dietary Guidelines score (DDG), with higher scores reflecting healthier dietary habits. PA was measured by the Short Questionnaire to Assess Health-enhancing PA score. Logistic regression analyses were performed between dietary/PA scores, and the prevalence/development and severity of HS. RESULTS: Compared to controls, HS patients scored lower on the LLDS [OR = 0.98; 95% CI 0.96-0.99], aMED [0.93; 0.89-0.97] and DDG [0.93; 0.88-0.97] with multivariable regression analysis. Overall, this indicates less adherence to dietary recommendations and consumption of a low-quality diet in the HS population. Lower adherence to the LLDS and DDG was also significantly associated with a higher likelihood to HS development in univariable regression analysis [0.96; 0.94-0.99 and 0.91; 0.84-0.99, respectively], and a trend of decreased adherence to the aMED [0.93; 0.85-1.02] was noted. Besides, PA levels were found significantly lower in HS patients (p ≤ 0.001). CONCLUSIONS AND RELEVANCE: Poor diet quality and lower quantities of PA were associated with HS in the general population. Identifying dietary and PA habits of HS patients can contribute to the development of prevention strategies for HS specifically, and for IMIDs in general.

A two-stage genome-wide association study of radiation-induced acute toxicity in head and neck cancer.

BACKGROUND: Most head and neck cancer (HNC) patients receive radiotherapy (RT) and develop toxicities. This genome-wide association study (GWAS) was designed to identify single nucleotide polymorphisms (SNPs) associated with common acute radiation-induced toxicities (RITs) in an HNC cohort. METHODS: A two-stage GWAS was performed in 1279 HNC patients treated with RT and prospectively scored for mucositis, xerostomia, sticky saliva, and dysphagia. The area under the curve (AUC) was used to estimate the average load of toxicity during RT. At the discovery study, multivariate linear regression was used in 957 patients, and the top-ranking SNPs were tested in 322 independent replication cohort. Next, the discovery and the replication studies were meta-analyzed. RESULTS: A region on 5q21.3 containing 16 SNPs showed genome-wide (GW) significance association at P-value < 5.0 × 10-8 with patient-rated acute xerostomia in the discovery study. The top signal was rs35542 with an adjusted effect size of 0.17*A (95% CI 0.12 to 0.23; P-value < = 3.78 × 10-9). The genome wide significant SNPs were located within three genes (EFNA5, FBXL17, and FER). In-silico functional analysis showed these genes may be involved in DNA damage response and co-expressed in minor salivary glands. We found 428 suggestive SNPs (P-value < 1.0 × 10-5) for other toxicities, taken to the replication study. Eleven of them showed a nominal association (P-value < 0.05). CONCLUSIONS: This GWAS suggested novel SNPs for patient-rated acute xerostomia in HNC patients. If validated, these SNPs and their related functional pathways could lead to a predictive assay to identify sensitive patients to radiation, which may eventually allow a more individualized RT treatment.